A Methodology for Assessing the Seismic Vulnerability of Highway Systems

Modern society is totally dependent on a complex and articulated infrastructure network of vital importance for the existence of the urban settlements scattered on the territory. On these infrastructure systems, usually indicated with the term lifelines, are entrusted numerous services and indispensable functions of the normal urban and human activity. The systems of the lifelines represent an essential element in all the urbanised areas which are subject to seismic risk. It is important that, in these zones, they are planned according to opportune criteria based on two fundamental assumptions: a) determination of the best territorial localization, avoiding, within limits, the places of higher dangerousness; b) application of constructive technologies finalized to the reduction of the vulnerability. Therefore it is indispensable that in any modern process of seismic risk assessment the study of the networks is taken in the rightful consideration, to be integrated with the traditional analyses of the buildings. The present paper moves in this direction, dedicating particular attention to one kind of lifeline: the highway system, proposing a methodology of analysis finalized to the assessment of the seismic vulnerability of the system.